Hi, this is probably an oversight. If it helps you implement the feature, please go ahead and add a sub-issue for solving the Iterator problem.
Best, Aljoscha On Tue, 21 Feb 2017 at 16:13 Lin Li <lincoln.8...@gmail.com> wrote: > Hi, > > When I try to implement > https://issues.apache.org/jira/browse/FLINK-5498 > via "dataset.coGroup(another dataset)" with a generated > CoGroupFunction.(CoGroupFunction > interface: public void coGroup(Iterable<IN1> first, Iterable<IN2> second, > Collector<O> out) > > I couldn't get the right results, then I saw the backend Iterator did > not supply a new instance when invoked the "Iterable.iterator()" after > debugging. > (see org.apache.flink.api.common.operators.util.ListKeyGroupedIterator, > it differs from usual iterable collections in java which will implement > the iterator() method that supply a new iterator instance for the > collection. And this is not mentioned either in comments or document.) > > IMO, iterable collections' new iterator instance requirements probably > useful for other cases, so is it necessary to add this feature? > Greatful if someone can tell me the motivation that ListKeyGroupedIterator > didn't supply a new iterator instance. > > What do you think? > > Best, Lincoln >
